The Q35 chipset of the 755 does not support P4 chips (not all LGA775's are interchangeable). The 755 is clearly the better machine (assuming it is still functional), so even if you could put the P4 processor in it, I'm not sure why you would want to. The P4 clock speed is faster, but it's not always about the clock speed (otherwise they would have kept increasing speeds rather than developing more computing cores) ... as osprey said, the P4 has only a single core. Looking them up on CPUBenchmark.net, the Pentium 4 3.2 has a score of 524, while the Core 2 Duo E4400 has a score of 1165. They aren't even in the same class.

The Q35 chipset of the 755 does not support P4 chips (not all LGA775's are interchangeable). The 755 is clearly the better machine (assuming it is still functional), so even if you could put the P4 processor in it, I'm not sure why you would want to. The P4 clock speed is faster, but it's not always about the clock speed (otherwise they would have kept increasing speeds rather than developing more computing cores) ... as osprey said, the P4 has only a single core. Looking them up on CPUBenchmark.net, the Pentium 4 3.2 has a score of 524, while the Core 2 Duo E4400 has a score of 1165. They aren't even in the same class.